Phytochromes are plant, cytoplasmic photoreceptors and far red light red, which in response to a given stimulus light to undergo photoconversion active form Pfr and migrate to the nucleus. Recent studies show that phytochromes can phosphorylate a number of proteins (PKS1, Aux / IAA, cryptochromes, NDPK2) or as a result of direct interaction with the relevant nuclear proteins (PIF3, HFR1/REP/RSF1, PIF4, ELF3, ARR4) are involved in the regulation of trankrypcji genes. Cloned a number of genes encoding proteins functioning in pathways activated by PhyA or PhyB, where they play the role of positive and negative regulators fotomorfogenezy and the internal clock. A relatively large number of proteins (COP1, sygnałosom COP9, COP10) participate in light-regulated ubiquitination and proteasomal degradation of proteins regulating transcription (HY5 possible, HYH, LAF1).